Studies on the Quantitative Estimation of Alkaloids by Means of Immiscible Solvents*

CONTRIBUTED AND SELECTED STUD I E S ON THE QUAKTI‘TATIVE ESTIMATI ON OF ALKALOIDS BY MEANS O F IMlMISCIBLE SOLVENTS.* BY GEORGE D. BEXL A N D H A R R Y F. LEWIS. I.

INTRODUCTION : DISCUSSION O F T H E PROBLE-Id.

One of the oldest and most widely used methods of alkaloidal assay is based upon the general principle that alkaloids themselves are quite insoluble in water and soluble in organic solvents, while their salts are soluble in water and insoluble in the organic solvents. The method of alkaloidal assay based upon this principle is known as the “shaking out” process familiar through its connection with the Dragendorff’ method of plant analysis and the Stas-Otto* poison assay. I t is assumed that the alkaloidal salt is practically insoluble in organic solvents and the alkaloid insoluble in neutral aqueous solutions. It also assumes that the salt is neither hydrolyzed by the aqueous solvent nor decomposed by the organic solvent. Both Dragendorff and Otto certainly realized that the principles were not absolute. Dragendorff made exception to the rule in the case of the almost quantitative removal of caffeine and the removal of traces of veratrine by benzene and of theobromine, colchicine, papaverine, narceine and traces of narcotine by chloroform from acid aqueous solution of the alkaloids. Otto recognized the fact that ether took up traces of colchicine, papaverine, narcotine, veratrine and atropine from their acid solution, In most alkaloidal assays of this type, the acid aqueous solution obtained by the extraction of the sample with dilute acid is shaken out with the organic solvent, in order to remove from the mixture those substances which might later appear with the alkaloid, causing inaccurate results in the assay. Such substances are coloring matter, essential oils, bitter principles, tannins, etc. After this the acid aqueous solution is made alkaline and shaken out with more immiscible solvent, removing the alkaloid in more or less pure condition. Purification is completed by shaking out this chloroform or ether solution with acid, making the acid solution alkaline and shaking out with more chloroform or ether. This is done several times. Finally, the organic solvent is removed by evaporation, and the residue determined by direct weight or by dissolving in standard acid and titrating the excess with standard alkali. During the process, several sources of error are being introduced. In the first place, the alkaloidal salt may be slightly soluble in the organic solvent. There is also the possibility of the salt being hydrolyzed by the water present into free alkaloid and acid. This free alkaloid would be easily soluble in the organic solvent. There are some cases known where the organic solvent either decomposes the alkaloid or else combines with it. These factors may cause a decrease in the amount of alkaloid in the acid solution with a corresponding decrease in the total alkaloid at the end of the assay. During the removal of the alkaloid from an alkaline solution by extraction with organic solvent, any insolubility of the alkaloid in the solvent and solubility in ~

.

-

-

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___

*This paper‘presents the essential parts of the thesis presented by Mr. Lewis in partial fulfilment of the requirements for the degree of Doctor of Philo5ophy in Chemistry in the Graduate School of the University of Illinois. @ 812

AMERICAN PHARMACEUTICAL ASSOCIATION

813

the alkaline solution will cause low results. This last, however, is not a great source of error, except in the extraction of certain alkaloids with ether. And finally, the shaking out of the alkaloidal solution in organic solvent introduces the problem of the possible insolubility of the salt formed in the acid solution or, if not its insolubility, its slow solubility. This is very apparent in the case of the salts of strychnine. I t is the purpose of this work to obtain such results as will describe the partition of the alkaloid between the acid layer and the immiscible solvent, using different acids under different concentration conditions. Iri order to obtain more complete data, the equilibrium conditions were determined, starting with an acid solution of the alkaloid and, as well, shaking out the solution of the alkaloid in organic solvent with an acid. Thus it is hoped that the following conditions might be established for each alkaloid: (a) Which salt is most insoluble in chloroform or ether, and what concentration of acid is most favorable to this condition. ( b ) Which acid, and in what concentration, removes the alkaloid most completely from its solution in chloroform or ether. I n order to put the results obtained in the form mos; quickly available, a new term, that of extraction factor, has been introduced and the factor calculated for the different sets of conditions obtained in the course of the research. By extraction factor is meant the ratio of the amount of alkaloid in the layer of added solvent to the amount originally present in the first solution. For practical purposes, this would be a far better value to have than that of the partition ratio or the sum of the partition ratios for the different alkaloidal molecular species present. The extraction factor shows at a glance the completeness of the extraction, an indication of the value of extraction under those conditions. The partition ratiotells only the partition of one molecular species between two layers of equal volume, by definition of the term pahition ratio. 11. HISTORICAL.

Attention was first called to the quantitative solution of the problem through an article published by Dr. C. Kippenberger3 in 1897. I n this paper he states clearly the possibilities of error in alkaloidal estimation through hydrolysis of the salt with the subsequent solution of the free alkaloid. H e suggests the use of chloroform or chloroform containing a little alcohol as solvents. Three years later Kippenberger' published a second paper, in which he endeavored to establish the question 6n a firmer basis. H e worked with the alkaloids strychnine, brucine, atropine, morphine, aconitine, veratrine, papaverine, narceine, codeine, emetine, pelletierine, cocaine, quinine, narcotine, coniine, sparteine, thebaine, hyoscyamine, daturine, scopolamine and the base caffeine. For shaking out he used chloroform and ether. The action of the salts of the following acids was studied: Hydrochlo?ic acid, 21.9 percent, HCl ; sulphuric acid, 40.1 percent, H,SO, : tartaric acid ; oxalic acid. In some cases, sodium chloride was added to the acid solution and its effect observed. The alkaloid was dissolved with an excess of acid in 70 Cc. of water, and 50 Cc. of the immiscible solvent added. This mixture was shaken in a separatory funnel for about three minutes. After fully clearing, the layers were separated and the chloroform or ether layer washed with a few Cc. of water. The organic solvent was then evaporated on a water-bath and the residue, alkaloid plus alkaloidal salt, dried over concentrated sulphuric acid. The amounts of alkaloid and alkaloidal salt were determined in the following manner : the residue was dissolved

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standard acid and the excess acid titrated back with standard in an excess of alkali. This value for acid neutralized by alkaloid indicated the amount of free alkaloid present in the residue. The solution was then made alkaline with a slight excess of sodium hydroxide and extracted again with chloroform. The amount of total alkaloid was obtained by evaporation of the solvent and solution of the residue in standard acid with titration for excess acid as before. Subtraction of the first value, that of the fre? alkaloid from the second, or total alkaloid value will give the amount of alkaloid present in the residue. as salt. The results are found in the following tables. The column containing the strength of acidity was compiled by the authors of this paper, from the data of Kippenberger.

-

TABLE I. EXTRACTION OF

AN

ALKALOID BY

ITSSOLUTION (KIPPENBERGER).

CHLOROFORM FROM

Amount of alkaloid in 50 Cc. CHClr.

Alkaloid solution in 70 Cc. water.

Gm

0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2

Strychnine.. ........................ 0.0910 Brucine ............................. 0.0798 0.0014 Atropine.. ........................... Morphine. ................................ Aconitine. .......................... 0.097 1 Veratrine. .......................... 0.0807 Trace Codeine.. .......................... Cocaine. ........................... 0.002 1 Quinine.. ........................... Trace

Indicator.

. Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin

IN

HYDROCHLORIC ACID Alkaloid.

Strength of acid.

0.15N 0.075N 0.075N 0.075N 0.03N 0.075N 0.03N 0.015N 0.03N

Free.

Salt.

0.0114 0.0056

0.0806 0.0742

0.0158 0.0077

0.0813 0.0730

TABLE 11.

EXTRACTION OF A N ALKALOID BY CHLOROFORM FROM ITS SOLUTION I N SULPHURIC ACID (KIPPENBERGER). Amount CHCL.

Gm.

0.2 Strychnine.. ........................ 0.2 Brucine. ........................... 0.2 Atropine. ........................... 0.2 Morphine.. ......................... 0.2 Aconitine. ..........................

Trace 0.0020

......

......

0.0120 0.0064 Trace Trace

0.2 Veratrine.. ......................... 0.2 Codeine.. .......................... 0.2 Quinine.. .......................... e

EXTRACTION OF AN

......

......

Azolitmin Azolitmin

Azolitmin

Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin

0.17N 0.17N 0.034N 0.034N 0.017N 0.085N 0.255N 0.017N

Free.

Salt.

0.0123

0.0064

TABLE 111. ALKALOID BY CHLOROFORM FROM ITSSOLUTION I N A MIXTUREOF CHLORIC ACID AND SODIUM CHLORIDE (KIPPENBERGER).

Alkaloid solution in 7 0 Cc. water.

Gm.

Alkaloid.

' , ' , " ~Indicator. ~ ~ ~Strength of acid.

Alkaloid solution in 70 Cc. water.

0.2 Atropine, 14 Cc. NaC1.. .... 0.2 Atropine, 14 Cc. NaCI.. . . . . 0.2 Quinine, 14 Cc. NaCl . . . . . . 0.2 Aconitine, 14 Cc. NaCI.. ... 0.2 Quinine.. . . . . . . . . . . . . . . . . .

Amount of alkaloid in 50 Cc. CHClr.

Indicator.

0.0192 0.0149 0.0100 0.2160 0.0057

Azolitmin Azolitmin Haematoxylin Azolitmin Haematoxylin

Strength of acid.

Alkaloid. Free.

Salt.

0.075N ...... 0.015N ~. .....

Trace Trace

0.03N 0.017N

~

0.03N

HYDRO-

:::::: 0.0306

0017 0004

~ t ~ 0.1854

Acid Neutral saltsalt

~

~

~

815

AMERICAN PHARMACEUTICAL ASSOCIATION TABLE IV. EXTRACTION OF A N ALKALOID BY CHLOROFORM FROM ITSSOLUTION I N TARTARIC ACID (KIPPENIERGER). Alkaloid solution in 70 Cc. water.

Gm.

Amount of alkaloid in 50 Cc. CHClr.

0.2 Strychnine.. . . . . . . . . . . . . . . 0.0020 0.4 Tartaric Acid. . . . . . . . . . . . . 0.4 Brucine.. . . . . . . . . . . . . . . . . . 0.0032 0.4 Tartaric Acid. . . . . . . . . . . . .

Indic tor.

Strength of acid.

Azolitmin

......

Azolitmin

......

Alkaloid. Free.

Salt.

TABLE V. RESULTSOF SHAKING OUTTHE ACIDALKALOIDAL SOLUTION WITH ETHER, UNDERTHE SAME CONDITIONS A S BEFORE ( KIPPENBERCER). FROM HYDROCHLORIC ACID SOLUTION.

Ether took up : Narcotine. .............. .0.0002 grammes. Caffeine.. ............... .0.0112 grammes, as free caffeine. The following were found in noticeable traces : Aconitine, narceine, and emetine. Nonk of the other alkaloids gave up a trace to ether. FROM SULPHURIC ACID SOLUTION.

Ether took up : Caffeine. ................ .0.0083grammes as free caffeine. The following were found in noticeable amounts : Aconitine, papaverine, narceine, emetine and narcotine, also very slight traces of veratrine, strychnine, and codeine. THE ADDITION OF SODIUW CHLORIDE TO THE SOLUTIONS CAVE THE FOLLOWING RESULTS :

( a ) From hydrochloric acid in noticeable traces :

Narcotine, atropine, and quinine. ( b ) From sulphuric acid solution : Aconitine. Ether removed neither brucine nor strychnine from tartaric acid solutions.

In 1901, Hans Proelss6 gave a short description of the behavior of alkaloidal solutions toward different solvents. The work was divided in two parts : The first to determine the best solvent for the alkaloids as a class, and the second, the best solvent for the individual alkaloids. He compared the relative extractive powers of ether, chloroform, and benzene, and also mixtures of ether and chloroform, and alcohol and chloroform, for the alkaloids picrotoxin, veratrine, strychnine, atropine, codeine, and morphine. His method consisted in dissolving 0.1 gramme of alkaloid in 50 Cc. of water containing a few drops of hydrochloric acid. After maliing alkaline with sodium carbonate, the aqueous solution was extracted three times with the solvent. He states that constant results could not be obtained of sufficient accuracy to be anything more than comparative. 1. THEBESTSOLVENT FOR ALKALOIDS I N GENERAL. Solvent.

Results.

Ether. ..................... ..Very good with colchicine, brucine. Chloroform. .................Very good with colchicine, brucine, digitalin, veratrine, atropine, strychnine. Chloroform and ether. .......Very good with colchicine, atropine, veratrine, picrotoxin. Chloroform and alcohol. .Very good with colchicine, veratrine, digitalin, atropine, codeine, morphine plus potassium bicarbonate. Benzene .Very good with colchicine, strychnine, atropine, codeine, picrotoxin.

....

....................

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In conclusion he states that the best shaking-out liquid for alkaloids in general is chloroform, because of the solubility of most of the alkaloids in chloroform. 2. THEBEST SHAKING-OUT LIQUIDFOR T H E INDIVIDUAL ALKALOIDS. Alkaloids.

.

Results.

Atropine. ....................Any solvent satisfactory. Brucine.. .................. , . S a m e as for picrotoxin. Codeine. .................... .Alcohol plus chloroform, benzene. Colchicine .................. .Any solvent satisfactory. Morphine. .................. .Alcohol plus chloroform from potassium carbonate solution. Picrotoxin. ................. .Ether. chloroform from sodium carbonate-ammonium hydroxide solution. Strychnine. ................. .Chloroform, alcohol plus chloroform, benzenk from sodium carbonate-ammoniacal solution. Veratrine. .................. .Chloroform, ether plus chloroform, ether and benzene from ammoniacal solution.

In conclusion, he states that emulsions form easiest with benzene and least with ether. Ed. Springer,6 in 1902, studied the effect of the solvent chloroform on the extraction of the following alkaloids : Morphine, coniine, narcotine, strychnine, quinine, codeine, veratrine, and cocaine from solutions made acid with sulphuric, phosphoric, hydrochloric, tartaric, acetic, oxalic and citric acids. The amount of alkaloid in the residue after evaporation of chloroform was determined by titration in the same way that Kippenberger did. For some reason, he was unable t o obtain check results, and so his work is of no value from a quantitative stand-point. The following are his results : Aconitine.-Aconitine is removed as the salt from hydrochloric acid and as the pure salt in traces from the sulphuric acid solution. Atropi?ze.-From hydrochloric acid, traces were removed as the salt ; from sulphuric acid, traces as the free alkaloid; traces were found from the tartaric acid solution, also. Cocaine.-Some alkaloid is extracted from sulphuric and hydrochloric acid solutions, where the acid is present in small concentration. Codeine.-Codeine is not found in the chloroform residues from extraction of solutions of alkaloids in phosphoric, tartaric, oxalic, citric, and sulphuric acids, although in the last case it was found that if the concentration of the acid was low enough, some of the alkaloid would be removed as the free base. Morphine, Coniine, and Nicotine.-No alkaloid was extracted from solutions made acid with the following acids : Hydrochloric, sulphuric and phosphoric. Narcotine.-Xarcotine is removed from both hydrochloric and sulphuric acid solutions, partly as base and partly as salt. Quiniwe.-No alkaloid is removed from solutions of the sulphate, tartrate or phosphate, Some quinine is removed as the hydrochloride. Strychnine.-About 25 percent was removed from the hydrochloric acid solution as the salt. Slight traces were removed from the other acid solutions. Veratrine.-Veratrine is removed in traces in solutions containing small amounts of tartaric, sulphuric, and citric acids, but such is not the case with large excess of sulphuric or phosphoric acids. From this, it may be drawn that chloroform is a “good solvent” for the hydrochloric acid salts of the alkaloids. The solubility of the hydrochlorides is so great, in fact, that, if in excess of acid, the salt is taken over cempletely as the Salt, and

AMERICAN PHARMACEUTICAL ASSOCIATION

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only in the case of the weak base narcotine could traces of the free alkaloid be found in the chloroform extract. From the table, one would expect to find in the chloroform extract from the sulphuric acid solution in the Dragendorff assay, aconitine and narcotine, as well as the alkaloids mentioned by Dragendorff himself. Strychnine, veratrine and atropine might also be found in small amounts. TABLE VI. BEHAVIOR OF NEUTRAL AND ACIDIFIED ALKALOIDAL SALTSOLUTIONS TOWARD EXTRACTION WITH CHLOROFORM (SIMMER). Alkaloidal salt.

Strychnine hydrochloride. . . . . . . . . . . . . . .

Strychnine hydrobromide. . . . . . . Strychnine hydriodide . . . . . . . . . . . . . . . . . . . . Strychnine nitrate. . . . . . . . . . . . . . . . . . . . . . . . Strychnine sulphate

. . .. .. ..... . . .. . . . .. . .

Veratrine hydrochloride. . . . . . . . . . . . . . . . . . . Veratrine nitrate. . . . . . . . . . . . . . . . . . . . . . . . .

.

Veratrine sulphate . . . . . . . . . . . . . . . . . . . . . . Veratrine tartrate , . . . . . . . . . . . . . . . . . . . . . . Morphine hydrochloride . . . . . . . . . . . . . . . . Motphine sulphate . . . . . . . . . . . . . . . . . . . . . . . Morphine acetate , , . . . . . . . . . . . . . . . . . . . . . . Codeine hydrochloride . . . . . . . . . . . . . . . . . . . . Codeine hydrobromide. . . . . . . . . . . . . . . . . . . .

Amount in 5 0 Gm. water.

Strength. acid per cent.

0.2377 0.2377 0.2377 0.2377 0.2377 0.2480 0.2480 0.2480 0.2760 0.2377 0.2377 0.2610 0.2610 0.2110 0.2110 0.2110 0.2200 0.2200 0.2150 0.2150 0.2230 0.2230 0.2230 0.2470 0.2470 0.2470 0.2500 0.2500 0.2630 0.2340 0.2340 0.2340 0.2620 0.2620 0.2620 0.2620 0.2470 0.2470 0.2360 0.2480 0.2480

0.0 0.1 1.0 10.0 25.0 0.0 0.1 1.o 0.0 0.0 1.o 0.0 1.o 0.0 0.1 10.0 0.0 1.o 0.0 0.1 0.1 2.0 5.0 0.0 0.1 5.0 0.0 0.1 0.0 0.0 0.1 10.0 0.0 0.1 10.0 25.0 0.0 0.1 0.1 0.0 0.1 0.0 . . 0.1 1.o 10.0 0.0 0.1 0.0 0.1 1.o 5.0 0.0 0.1 10.0

~

~

Codeine sulphate. . . . . . . . . . . . . . . . . . . . . Codeine tartrate . . . . . . . . . . . . . . . . . . . . . . . . . Codeine citrate . . . . . , . . . . . . . . . . . . . . . . . . . . Cocaine hydrochloride. . . . . . . . . . . . . . . . . . . .

. .. . . . . . . . . . . . . . . . . . . . . Cocaine tartrate. . . . . . . . . . . . . . . . . . . . . . . . . Cocaine sulphate..

Atropine hydrochloride

.....

~~~~

~~~~

0.2240 0.2640 0.2640 0.2310 0.2310 0.2310 0.2310 0.2250 0.2250 0.2250

.

Grarnmea alkaloid. Total.

Free.

Salt.

0.0153 0.0083 0.0250 0.0559 0.2330

0.0142 0 0 0 0 0.0133 0 0 0.0250 0.0233 0

0.0016 0.0083 0.0250 0.0559 0.2330 0.0067 0.0167 0.0350 0.0317 0.0050 0.0350

0.0499 0 0 0.0405 ~ . 0 0.0371

0.003 1 0.0327 0.1248 0 0.0811 0

0.0842 0.0155

0 0

0.0045 0 0 0.0037 0 0.0197 0.0371 0 0 0.0126

0 0 0 0 0 0 0 0.0015 0.0079 0

0 0 0.0276

0.0110 0.0079 0

0.0110 0.0395 0.0158 0.0490 0.0015 0 0 0.0143

0 ' 0 0

0.0543 0.0528 0.0332 0.0015

0

0.0560 0.0283 0.0350

Trace Trace 0.0530 0.0327 0.1248 0.0405 .. ~ 0.0811 0.0374

Traces 0.0842 0.0155

Traces 0.0045 0

0 0.0037 0 0.0197

Traces 0.0110 0.0079 0.0276

Traces 0.0110 0.0395 0.0158 0.0490 0.0037 0.0045 0.0075 0.0143

Traces 0.0543 0.0528 0.0332 0.0015

0

0.0022 0.0045 0.0075 0

0 0 0

Traces of free atropine. Traces of free atropine. 0.0028 0 0.0028

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TABLE VII. BEHAVIOR OF NEUTRAL AND ACIDIFIEDAKLALOIDALSALTSOLUTIONS TOWARD EXTRACTION WITH BENZENE (SIMMER). Alkaloidal salt.

Amount Strength, in 50 Gm. acid of water. per cent.

Strychnine hydrochloride. ................ , 0.2377 0.2377 0.2377 0.2377 0.2480 Strychnine hydrobromide. . . . . . . . . . . . . . 0.2480 0.2760 Strychnine hydriodide .................... 0.2610 Strychnine sulphate ....................... Strychnine nitrate. ....................... 0.2377 0.2150 Veratrine sulphate. ....................... 0.2150 Codeine hvdrochloride .................... 0.2340 0.2340 0.2340 Codeine hydrobromide. ................... 0.2620 0.2620 Codeine sulphate.. ....................... 0.2470 Codeine citrate.. ......................... 0.2480

0.0 0.1 1.o 10.0 0.0 0.1 0.0 0.0 0.1 0.0 0.1 0.0 0.1 10.0 0.0 1.0 0.0 0.0

Grammes alkaloid. Total.

Free.

Salt.

0.0075

0.0075

0

0

0 0

0

0.0033

0

0.0033 0

0 0

0.0055 0 0 0.0023

0 0 0

0 0.0031 0.0023

0 0

0

Traces 0.0033 Traces 0.0033 0 Traces Traces Traces 0.0055 0 0 0.0023 0 0.003 1 0.0023

0

'

0 0

In 1906, Simmer7 published an important paper on this subject. The work was divided in three parts : 1. The behavior of the salts of .the common alkaloids toward extraction by chloroform and other important solvents. : 2. The appearance of decomposition through treatment with chloroform. 3. The reducing action of the alkaloids. Simmer prepared an aqueous solution of the alkaloidal salt, containing 0.2 gramme of the free alkaloid to 50 Cc. of solution, or 0.4 percent of the free alkaloid. H e then acidified with the different acids until he obtained the desired concentrations. Simmer neglected to state definitely the amount of chloroform used in the extraction, but the general tone of the paper would lead one to believe that he used equal amounts of chloroform and aqueous solution. n e s e were mixed and the extraction carried on for an hour. At the end of that time, the layers were separated and the chloroform evaporated. The amount of free alkaloid and alkaloidal salt was determined in the residue in the usual manner. It will be seen from the tables that many neutral salts are extracted by both ahloroform and benzene; this is especially true in the cases of the salts of the nitric and halogen acids. With strychnine hydrochloride, the least amount of salt is extracted from the neutral solution and the most from the solution that contains a 10 percent excess of acid ; the 25 percent acid gives up less alkaloid than the 10 percent solution. The behavior of the weak bases colchicine, caffeine, narcotine, papaverine, and antipyrine is different. In strong hydrochloric acid solution of colchicine, there is as much alkaloid removed by the chloroform as from the aqueous solution. The same is true with sulphuric or phosphoric acid solutions. Caffeine, thebaine and narcotine are removed from weak tartaric acid solutions as easily as from stronger acid solutions. Papaverine, narcotine, and thebaine are removed simply as salts and not as free bases.

2.

THE DECOMPOSING POWER OF T H E ALKALOIDS O N CHLOROFORM.

The observation had been made by many authors that extraction of the alkaloids with chloroform is attended with a decomposition of the chloroform, giving rise to free hydrochloric acid.

AMERICAN PHAR@MACEUTICAL ASSOCIATION

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In order to determine this, Simmer extracted a mixture of 50 Gm. of water and 2 Gm. of finely powdered alkaloid with 50 Gm. of chloroform for eight hours. First the water was tested. This always gave an opalescence with silver nitrate, but showed itself to be free from alkaloid, except in the few cases due to the relative insolubility of the alkaloid in chloroform. The chloroform layer was then evaporated and the residue dissolved in water containing a sufficient amount of sulphuric acid. Silver nitrate solution was then added. When a definite precipitate was observed, this was filtered, dissolved in ammonia and precipitated again with nitric acid. Then the pure precipitate was filtered in a Gooch crucible and weighed. TABLE VIII. AgCl from the chloroform layer.

Alkaloid, 2 Gm.

Atropine.......................................... B y c g e . . ......................................... Qumme........................................... Cinchonidine....................................... Cinchonine........................................ Cocaine........................................... Codeine........................................... Morphine......................................... Narcotine......................................... Nicotine. ......................................... Strychnine........................................ Veratrine.. .......................................

Corresponding to-

0.0038 0.0138 Traces * Traces Traces 0.0021, Traces 0 0 Traces 0.0035 0.0043

HCl.

Alkaloid.

0.0009 0.0033

0.0072 0.0333

0.0005

0.0042

0.0008 0.0010

0.0073 0.0173

’

I

Thus we see that the action of the alkaloid upon the chloroform is negligible, except in the cases of brucine and veratrine. Marden and Elliott,s in 1914, published a paper on the methods of extraction by immiscible solvents from the point of view of the distribution ratios. They shook out the alkaloid6 aconitine, atropine, codeine, coniine, morphine, quinine, and strychnine with the solvents chloroform and ether. Ammonium hydroxide was used to make the acid solution alkaline. From the distribution coefficient and a certain subsequent algebraic calculation, they could determine the number of extractions necessary to remove 99.9 percent of the alkaloid. The distribution ratio (6)is indicated by the expression.

c

Concentration in 10 Cc. of water C = = (d) Concentration in 10 Cc. of non-aqueous solvent

The algebraic expression for the calculation of the number of shakings necessary for an extraction is’indicated by ?n =

xo

(A)” where e+da

a = volume of the aqueous solvent. c =volume of non-aqueous solvent. d = distribution ratio. xo =original amount of material to be extracted in the aqueous layer. x , =amount of material in the water layer after t z extractions.

In the system aconitine, ether and aqueous ammoniacal solution, using 100 Cc. water, 5 Cc. ammonium hydroxide, and 50 Cc. of ether, the following result was obtained, d = 0.140; but on substituting 30 Cc. of chloroform for the 50 Cc. of ether, the value of d became 0;017. Atropine.-The distribution ratio in the system water and chloroform was

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JOURNAL O F THE

found to be very small and three extractions with 10 Cc. of chloroform from 50 Cc. of the aqueous solution were sufficient to remove the atropine. Codeine.-In the system, 100 Cc. water, 5 Cc. ammonium hydroxide, and 50 Cc. ether, d had a value of 0.939. If 30 Cc. chloroform were substituted for the ether, the value became 0.0067. Coniine.-Owing to the volatility of the coniine, it was very difficult to get the partition ratio. Morphine.-In the system, saturated aqueous solution of potassium carbonate and a mixture of methyl alcohol and chloroform, d possessed a value of 0.154,with variations from 0.200 to 0.127. The value for the system, 100 Cc. water, containing 35 Gm. sodium chloride, and 45 Cc. of a 2 : l mixture of chloroform and ethyl alcohol was found to be 0.528. The value for d between water and chloroform-amyl alcohol mixtures was

0.345. Quinine.-Between water made alkaline with ammonium hydroxide and chloroform, quinine was found to possess such a low distribution coefficient that three washings of a 50 Cc. aqueous solution with 10 Cc. of chloroform were found to remove all of the alkaloid. Strychnine.-The authors determined the distribution coefficients for systems containing chloroform alone and in a mixture with ether in order to see which would prove more efficient, as there has been a great difference of usage. For the system, 100 Cc. of water, 2 Cc. of ammonium hydroxide, and 30 CC. of chloroform, d was found to be equal to 0.003, but on substituting a mixture of 1:3 chloroform and ether, the value 0.087 was obtained. S U M M A R Y OF THE HISTORICAL CIIAPTER.-h looking over the work that has been published on the subject of the quantitative estimation of the alkaloids by the shaking-out process, sufficient data will be found to establish the equilibrium conditions of the systems, alkaloidal hydrochlorides or sulphates between their acid solutions and chloroform or ether. Results are lacking, however, which will show the partition of alkaloidal tartrates between tartaric acid and those solvents. In addition the whole subject of the extraction of an alkaloid from its solution in chloroform by an acid has never been investigated. T f equilibrium is reached, this should give the same value as with the extraction of the acid salt solution by that solvent. In practice, it takes a long time with some of these systems and there are certain other factors entering in. 111. THEORETICAL CONSIDERATION.

I n an acid solution of a neutral alkaloidal salt the following equilibria are established : ( a ) The alkaloidal salt is in equilibrium with the free alkaloid and acid, due to the hydrolysis of the salt, and ( b ) The neutral salt and acid are in equilibrium with an acid salt. It is possible that more than one acid salt may be formed, in which case there will be as many more equilibrium reactions as there are acid salts formed. If chloroform is added to this system, and the mixture shaken, each of these equilibria may be affected. For example, the mass law equation for the hydrolysis of an alkaloidal salt is expressed by the following: Calkaloid Cealt

X

x Cacid = k, Cwata

AMERICAN PHARMACEUTICAL ASSOCIATION

821

where k is the mass law’constant. The removal of one of the constituents will cause a resultant shift in the other concentrations in order that k may remain constant. The presence of a great excess of acid will drive back the hydrolysis by increasing the value for the term Cacldwith the resultant decrease in value for the term Calkalold.A t the same time, solution of the alkaloid in chloroform will cause a decrease in the value, Calkalold, with a resultant further lowering of Cealtin order to restore equilibrium. This salt which is removed is hydrolyzed. So the result of the removal of free alkaloid is to increase the hydrolysis. Thus, in this system a t equilibrium the conditions existing are a resultant of these two equilibria which are progressing with opposite tendencies. To approach the equilibrium from the other direction, however, introduces a new factor, namely, the speed of solution of the newly-formed salt in acid solution. As the two immiscible layers are being shaken together, forming an intimate mixture of alkaloid dissolved in chloroform and acid in the water, the alkaloid molecule in the chloroform and the acid molecule in the aqueous acid liquid meet at the junction of these fine drops of the two solutions, and combine. I n case the acid is monobasic, the first result of the reaction is probably the formation of a neutral salt. In an excess of acid, the acid salt is then formed. With the dibasic acids, however, such as tartaric acid or sulphuric acid, the acid salt is formed first, similarly to the mechanism of the ncutralization of sulphuric acid with sodium hydroxide. As more alkaloid combines, there is a gradual change from the acid salt into the neutral salt. The neutral salt in many cases seems to be very slowly soluble at ordinary temperatures, although it goes easily into solution at boiling temperature. With the excess of acid, however, the first acid salt is formed, which in some cases is only slightly soluble in a small excess of acid. As the excess of acid becomes greater, the soluble higher acid salts are formed. Thus the solution in acid may be hastened by shaking out with fresh portions of acid, in order to get the alkaloid as the higher acid salt. This situation would not be met with where the salt solution is shaken with chloroform or ether, for in these cases the salt is dissolved at a much higher temperature and the solution cooled. IV. EXPERIMENTAL.

( a ) Preparation of some alkaloidal tartrates and a brief description of their properties : The neutral salts were prepared by dissolving the alkaloids in an aqueous acid solution, containing equivalent amounts of tartaric acid in a large excess of water, at the boiling temperature. I n the excess of hot water, the acid salt which forms first stays in solution and the remainder of the alkaloid completely neutralizes it. O n cooling the solution slowly, the neutral salt comes out in beautiful crystals. In one or two cases it was necessary to evaporate some of the solvent water in order to get the right concentration for crystallization. The mon-acid salt may be prepared by dissolving the alkaloid in a slight excess of acid, in a small quantity of hot water. On cooling the crystals of the acid salt will come out. These salts are further purified by crystallization from water several times. In this way the crystalline salts of ,brucine, cinchonine, cinchonidine, quinine, morphine, and strychnine were prepared. The alkaloids aconitine, atropine, cocaine. codeine, and veratrine were obtained in the form of tartrates for further investigation by simply dissolving the alkaloids in the proper concentration of acid, as their tartrate salts were amorphous.

822

JOURNAL O F THE

The neutral salts are characterized as follows : (The amount of alkaloid present represents the percent alkaloid in the anhydrous salt.) b'trychnine: M. P. 226"-227", browning a t 215". Crystalline form : beautiful white rosettes. Analysis : 81.68 percent strychnine. 15.00 percent water. Theoretical for (C,,H,,N,O,) ,.C4H,0,.8H,O : 81.66 percent strychnine. 15.20 percent water. Brucane: M. P. 236"-237", with decomposition; browns at 210". Crystalline form : white cubes. Analysis : 83.2 percent brucine. 9.1 percent water. Theoretical for (C,,H,,N,O,) ,.C,H,O,.SH,O : 83.7 percent brucine. 8.8 percent water. Quinke: M. P. 199", with browning. Crystalline form : fine white needles. Analysis : 81.28 percent quinine. 2.56 percent water. Theoretical for ( C,,H,,N202) ,.C,H,O,.H,O : 81.20 percent quinine. 2.3 percent water. Cinchonidine: M. P. 230"-231" with decomposition; browns at 218". Crystalline form : long white needles. Analysis : 79.68 percent cinchonidine. 4.60 percent water. Theoretical for ( C,,H,,N,O) ,.C4H,0,2H,0 : 79.69 percent cinchonidine. 4.64percent water. Cinchonine: M. P. 190", without either decomposition or browning. Crystalline form : short white needles. Analysis : 79.76 percent cinchonine. 2.8 percent water. Theoretical for ( C,,H,,N,O) ,.C,H,O,.H,O : 79.69 percent cinchonine. 2.4 percent water. The water of crystallization was determined by weighing the sample, heating at 110" to constant weight, and then dissolving the anhydrous salt in water. The so]ution was made alkaline and extracted twice with an excess of chloroform. The chloroform was evaporated and the residue heated to constant weight. The value obtained was that of the weight of the alkaloid in the sample of salt taken. From

AMERICAN PHARMACEUTICAL ASSOCIATION

823

the value of alkaloid and that of water of crystallization was calculated the formula of the salt. The one exception in this procedure was in the case of brucine where the residue from the chloroform extraction of the alkaline brucine solution was dissolved in standard acid and the excess acid titrated back with standard alkali. The acid salts were analyzed in the same manner. ( b ) Determination of the equilibrium conditions for the partition of the alkaloids and alkaloidal salts between aqueous neutral and acid solutions and an immiscible solvent (chloroform or ether) : 1. Extraction of the neutral or acid aqueous alkaloidal solution with chloroform and ether : 0.2 Gm. of the neutral alkaloidal salt was dissolved in 25 Cc. of the aqueous acid solution of a definite concentration. T o this were added 20 Cc. of chloroform or ether and the mixture was shaken in a Jena Erlenmeyer flask for two hours and a half, at a temperature of 25". The shaking was carried out in a water thermostat, accurate to within a tenth of a degree. The time of shaking was chosen after experiments were carried out to determine the time required for the reaction to come to equilibrium. It was found that in the case of strychnine tartrate only half this time was required. When that time had elapsed, the flasks were removed, the layers at once separated, and the chloroform or ether layer put in a small separatory funnel. After standing for about 10 minutes in order to make a clear separation, 10 Cc. of the chloroform solution were measured into a porcelain casserole, and the chloroform evaporated on a steam-bath. The residue was taken sulphuric acid, and the excess acid titrated back with standard up in 10 Cc. of N 50potassium hydroxide. Such indicators were used as would give the most accurate results for the individual alkaloids. The selection of indicator was made after reference to Kippenberger's article. The value obtained in this way gave the amount of free alkaloid present in the residue. The neutral solution was made alkaline and extracted with chloroform. After separation, the solvent was evaporated and the residue again taken up in standard acid and titrated back with standard alkali. This gave the value for the total alkaloid. By subtracting the first value from the second, the amount of alkaloid present, combined with acid in the form of salt, was obtained. With morphine, a slightly different procedure was carried out. In determining the amount of total alkaloid, the neutral solution after the first titration was made alkaline with ammonium hydroxide, since sodium and potassium hydroxide form salts with morphine which are soluble in alkaline solution. The alkaline solution was then extracted with amyl alcohol, until it showed the absence of alkaloid, amyl alcohol being the best solvent for morphine which will answer the purpose. The solutions of the neutral salts were of the following acid strengths : Neutral, _- ,The equilibrium conditions were determined for the tartrate salts of the alkaloids aconitine, atropine, cinchonidine, cinchonine, cocaine, codeine, quinine, morphine, strychnine and veratrine, in tartaric acid solutions. The equilibrium conditions for the solutions of alkaloidal sulphates in sulphuric acid and hvdrochlorides in hydrochloric acid were worked out with the idea of supplementing and adding to those values obtained by Kippenberger and Simmer. Table IX gives the results of the extraction of the salt solution by chloroform, and Table X, the values obtained by the extraction with ether. 2. Conditions at equilibrium in systems in which the alkaloid is being removed from its chloroform solution by an acid.

2

,-&

JOURNAL O F THE

824

TABLE IX. Alkaloid.

Strychnine.

. . . . . . ... .

. . . . . . . . . . .. . . .

Acid.

Strength.

HTr HTr HTr HTr Sulph. Sulph. Sulph. Sulph. Sulph. HCl HC1 HC1

N/2 N/4 N/8 Neut. N/2 Nj4

NIX

Njso

Neut. N/2 N/4 N/8 Neut. N/2 N/4 N/8 Neut. N/2

HTr HTr HTr HTr Sulph. N/4 Sulph. Nji Sulph. Sulph. Neut. N/2 Cinchonidine. . . . . . . HTr HTr N/4 HTr N/8 Neut. HTr Sulph. N/2 Sulph. suhh. SuGh. Neut. N/2 Cinchonine. . . . . . . . . . HTr HTr N/4 HTr N/8 HTr Neut. Caffeine.. . . . . . . . . . . . . Sulph. N/2 Sulph. N/4 Sulph. N/8 Sulph. Neut. N/2 Cocaine.. . . . . . . . . . . . . HC1 HCl N/4 HC1 N/8 HC1 Neut. -N/2 Codeine. .. . . . . . . . . . HTr HTr N/4 HTr N/8 HTr Neut. N/2 HTr Quinine.. HTr N/4 HTr _ _ _N ./ 8 Neutral i a k b u t Sulph. N/2 Subh. N/4 Sulbh. N/8 Sulph. Neut. N/2 ~~-~ Aconitine.. . . , . HTr HTr Nj4 HTr N/8 HTr Neut. N/2 Atropine. . .. . . HTr HTr N/4 HTr N/8 HTr Neut. Morphine. HTr N/2 HTr N/4 HTr N/8 HTr Neut. Veratrine . ..... . N/2 HTr HTr N/4 HTr N/8 HTr Neut.

Brucine.

. .. .

3;

... . .

.

.

.

...

. . . .. . . .. . . .. .

. . . . . .. .

. . .. . ... .

. . . .. .. .. . . . .

.. ..

. ..

Grammes alkaloid in 20 c c . chloroform. Salt. Total. Free.

0 0 0 0.0120 0 0

n

0

0.0127 0.0522 0.0424 0.0394 0.0085 0 0 0.0026 0.0076 0

n

0

0.0143 0.0012 0.0024 0.0018 0.0024 0

0 0 0 0.0104

0 0 0 0 0.0127 0 0 0 0.0081 0 0 0.0026 0.0076 0 0 0 0.0143 0.0012 0.0024 0.0018 0.0024 0 0 0 0.0086 0 0 0 0 0.1928 0.1930 0.1300 0.1032 0 0 0.0432 0 0 0 0.0018 0.0046 0 0.0014 0.0014

Indicator.

0 Azolitmin Azolitmin 0 0 Azolitmin 0.0016 Azolitmin Azolitmin 0 0 . Azolitmin 0 ,Azolitmin Azolitmin 0 Azolitmin 0 0.0522 Azolitmin 0.0424 Azolitmin 0.0394 Azolitmin 0.0005 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin

0 0 0 0 0 0

.

Azolitmin Azolitmin Azolitmin 0 0 Azolitmin Azolitmin 0.0086 n Azolitmin 0 Azolitmin 0 0 Azolitmin 0 0.0016 Azolitmin 0.0016 0 0.1928 weight of residue 0 0.1930 weight of residue 0 0.1300 weight of residue 0 0.1032 weight of residue 0 Iodeosin 0 0 Iodeosin 0 0 0.0432 Iodeosin 0.0432 Iodeosin 0.0432 n 0 Azolitmin 0 0 Azolitmin 0 Azolitmin 0.0018 0 Azolitmin 0.0046 0.0014 Azolitmin 0.0014 0.0014 Azolitmin 0.0028 0.0014 Azolitmin 0.0018 slightly soluble in water. 0 Azolitmin 0 0 0 0 0 Azolitmin 0 0 0 Azolitmin 0 0 Azolitmin 0 0 0 0 Cochineal 0.0537 Cochineal 0.0537 0 0.0099 Cochineal 0.0099 0 0.0099 Cochineal 0.0236 0.0136 0 0 0 Cochineal 0.0036 0.0036 0 Cochineal 0.0028 Cochineal 0.0010 0.0038 0 0.0018 0.0018 Cochineal 0 0 0 Cochineal 0 0 0 Cochineal 0 0 0 Cochineal 0 0 0 Cochineal 0.0049 0 0.0049 Cochineal 0 0.0116 0.0116 Cochineal 0 0.01 12 '0.0112 Cochineal 0 0.0294 0.0294 Cochineal

825

AMERICAN PHARMACEUTICAL ASSOCIATION TABLE

XI.

Grammes alkaloid in 20 Cc. ether. Alkaloid.

Strychnine.

. . . . . .. ... , ,

Acid.

Strength.

HTr HTr HTr HTr

0 0.0027 0 0 0.0040 0.0032 0 0 0 0 0.0018 0.0018 0 0.0024 0 0 0 0.0040 0 0 0.0014 0.0023 0 0 0 0 0 0

HTr HTr Sulph. Sulph. Sulph.

Sulph. SulDh.

Codeine.. . . . .

Aconitine.

Quinine.

Nj8 Neut. N/2 N/4 N/8 Neut. N /2 Nj4 N/8 Neut.

...

. . . . . . . . . .. . . . .

HTr _ _ HTr Sulph. Sulph. Suhh. Sulph. HTr HTr HTr Sulph. Sulph. ~~~

~

Total.

Free.

0 0 0 0 0 0

;;:

Nj8 Neut. N/2 N /4 N/8 Neut.

~ .

0.0023 0 0 0

0.0052 0.0060 0 0.0011 0.0014 0.0021 0 0 0 0 0 0 0.0011 0.0019 0 0 0.0014 0

0 0 0 0 0 0 0.0024

0.8027

n

0 ? 0.0032

0 0 0

0 ? ? 0 0.0012 0 0

0 0.0040 0 0 ? 0.0023 0 0 0 0

0 0 0 0 0 0 ? 0

0 ? ?

0 0 0 0 0 0 0 0.0011 0.0019 0 0 ? 0 0 0 0 0 0

0 0.0024

Salt.

Indicator'

Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin 0.8027 Azolitmin 0 Azo1itmin 0 Azolitmin Azolitmin ? Azolitmin 0 0 Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin 0 Azolitmin 0.0012 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin ? Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0.0023 Azolitmin Azolitmin 0 0 Cochineal 0 Cochineal ? Cochineal 0.0060 Cochineal 0 Cochineal ? Cochineal ? Cochineal 0.0021 Cochineal Cochineal 0 Cochineal 0 0 Cochineal Cochineal 0 0 Cochineal 0 Cochineal Cochineal 0 Cochineal 0 Azolitmin 0 Azolitmin 0 ? Azolitmin 0 Azolitmin Azolitmin 0 0 Azolitmin Azolitmin 0 Cochineal 0 Cochineal 0 Cochineal 0 Cochineal 0

1 Owing to the solubility of tartaric acid in ether, it is impossible to say whether the salt is present in the ether in the free state or as salt, in the extraction from acid solution.

JOURNAL O F THE

8%

0.2 Gm. of the alkaloid were dissolved in 20 Cc. of chloroform and 25 Cc. of the required concentration acid added. The mixture was shaken for two hours and a half, in the same manner as was the previous case, at 25". After separation of the two layers, the amount of alkaloid and alkaloidal salt in the chloroform layer was determined. The results are tabulated in Table XI. Owing to the insolubility of some of the alkaloids in ether, values were not always obtained for the use of this solvent. The chloroform solutions of the alkaloids were shaken out with sulphuric, In the case of hydrochloric and tartaric acids o! the concentrations, TN , -4N T, N strychnine, even more dilute acid solutions were used. In those cases where the salt formed is but slowly soluble in the acids, experiments were made to determine how many shakings would more quickly dissolve the salt, and what strength acid would be best. TABLE XI. Nature volume.

Alkaloid.

arid.

Aconitine. . . . . . . . . . . . . .

Atropine. . . . . . . . . . . . . . . Brucine . . . . . . . . . . . . . . . .

....

Cinchonhe. ......

.. .....

Cocaine. .........

cc. HTr 25 HTr 50 HTr 50 HC1 25 HC1 25 HC1 25 HTr 25 HTr 25 HTr 25 HTr 25 HTr 25 HTr 35 Sulph. 25 Sulph. 25 Sulph. 25 HC1 25 HCl 25 HC1 25

Sul-h. HE1 HC1 HC1 HTr HTr HTr Sulph. Sulph. Sulph. HC1 HC1 HC1 HTr HTr HTr Sulph. Sulph. Sul h. H& HC1 HC1

25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

stZenah.

Grammes alkaloid in 2 0 CC. chloroform. Total.

Free.

Salt.

0 0 0 0.0342 0.0257 0.0146 0.0146 0.0010 0 0 0.0014 0 0 0.0008 0.0012 0.0768 0.0583 0.0445 0 0 0 0 0 0.0012 0 0 0 0 0 0 0 0 0.0011

0 0 0 0 0 0 0.0010 0.0010 0 0 0.0014 0 0 0.0008 0.0012 0 0 0

0 0 0 0.0342 0.0257 0.0146 0 0 0 0 0 0 0 0 0 0.0768 0.0583 0.0445 0 0 0 0 0 0 0 0 0 0

0

0 0 0 0 0.0017 0 0 0 0 0

0

0 0 0 0 0 0.0012 0 0 0 0 0 0 0 0 0.0011 0 0 0 0 0 0.0017 0 . 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Indicator.

Cochineal Cochineal Cochineal Cochineal Cochineal Cochineal Cochineal Cochineal Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azolitmin Azoftmin Azolitmin Cochjneal cochineal Cochineal Cochineal Cochineal Cochineal Cochineal Cochineal Cochineal

AMERICAN PHARMACEUTICAL ASSOCIATION

827

TABLE XI.-Continued. Alka!oid.

,

Codeine . . . . . . . . . . . . . . . .

Quinine :.

...............

Strychnine.

.............

HTr HTr HTr Sulph. Sulph. Sul h. H81 HC1 HCl HTr HTr HTr Sulph. Sulph. Sul h. H& HC1 HC1 HTr HTr HTr HTr

cc. 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 50 100 100 100

HTr HTr HTr HC1 HCl HC1 HTr HTr

9 _.5_ 75 75 25 25 25 25 25 25

Sulph. Sulph. HCl HC1 HC1

25 25 25 25 25

HTr

_--.

Veratrine.

I

,

............

Grammes alkaloid in ao Cc. c hlorof o m .

Nature.,volume, acid.

Total.

0

0

.O 0 0

0 0

0 0

0 0 0 0 0 0 0 0 0 0 0 0.001 1 0.0011

:$:

0.0011 .. ~

N)8 N/12 N/25 N/2 Nj4 N/8 N/Z N/4

:\!

0.0011 0.0029 0.0125 0.0202 0.0250 0.0202 0.0020 0.0040

:$:

N/8

0.0740 0.0516 0.0426

Free.

0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 0

0 0 0 0

_ _

0 0 0 0 0 0 0.0020 0.0040 0 0 0 0 0 0 0

Salt.

Indicator.

Azolitrnin Azolitmin Azolitmin Azolitmin Azolitmin 0 Azolitmin 0 0 Azolitmin 0 Azolitmin 0 Azolitrnin Azolitrnin 0 Azolitmin 0 Azolitrnin 0 Azolitrnin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 Azolitrnin 0 Azolitmin 0 Azolitmin 0 Azolitmin 0 0.0011 Azolitrnin 0.0011- Azolitrnin 0.0011 Azolitrnin . 0.0011 Azolitrnin 0.0029 Azolitmin 0.0125 Azolitrnin 0.0202 Azolitmin 0.0250 Azolitmin 0.0202 Azolitmin 0.0020 Cochjneal 0 Cochineal 0 Cochineal 0 Cochineal .O Cochineal 0 Cochineal 0.0740 Cochjneal 0.0516 Cochmeal 0.0426 Cochineal

0 0 0 0

(c) Calculation of the extractioiz factors under the various equilibrium conditions examined, as well as those reported in the literature : The extraction factor is simply the ratio of the amount of alkaloid found in the layer of the added solvent to the amount originally present in the first solution, regardless of the.volumes of the two solutions. This gives an excellent idea of the efficiency of the different sets of extraction conditions. Table XI1 contains the data and values for the.extracti0.n factors for the alkaloidal tartrates between tartaric acid and chloroform. In Table XI11 will be found similar values where ether has been used as the solvent. The extraction factors for the sulphates between sulphuric acid and chloroform and of the hydrochlorides between hydrochloric acid and chloroform are found in Tables XIV and XV, respectively. Table XVI contains the values, using ether for the solvent, for the sulphates. The extraction factors for the extraction of the alkaloids from their chloroform solutions, by tartaric, sulphuric and hydrochloric acids, will be found in Table XVTI.

JOURNAL OF THE

828

TABLE XII. Alkaloid.

Strychnine.

. . . . . . . . .. . ,

Brucine. . . . . . . . . . . . .

., .

Cinchonidine . . . . . . . . . . ,

Cinchonine

Quinine.

... . . . . . . . . ..

. . . . . . . . . . .. . . ,

Aconitine. . . . . . . . . . . . . . . Atropine , . , , . . . . . . . . . . , Codeine. .. . . . .

.. . . . . . . .

Morphine. . . . . .

.

Veratrine. . . . . .

Chloroform.

Acid.

......

......

HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr

Original

Alkaloid.

Acid volume.

tota!

alkalcid.

Factor.

Volume.

20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

0 0 0.0104 0.0126 0 0 0.0026 0.0076 0.0012 0.0024 0.0018 0.0024 0 0 0 0.0016 0.0014 0.0028 0.0028 0 0.0053 0.0099 0.0360 0 0.0036 0.0039 0.0018 0 0 0.0018 0.0046 0 0 0 0 0.0049 0.0116 0.0112 0.0294

25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

0.1650 0.1650 0.1650 0.1650 0.1680 0.1680 0.1680 0.1680 0.1595 0.1595 0.1595 0.1595 0.1595 0.1595 0.1595 0.1595 0.1625 0.1625 0.1625 0.1930 0.1930 0.1930 0.1930 0.1585 0.1585 0.1585 0.1585 0.1600 0.1600 0.1600 0.1600 0.1585 0.1585 0.1585 0.1585 0.1775 0.1775 0.1775 0.1775

0 0 0.0634 0.0768 0 0 0.0154 0.0453 0.0076 0.0153 0.01 14 0.0153 0 0 0 0.0100 0.0086 0.0172 0.0172 0 0.0274 0.0512 0.1240 0 0.0217 0.0245 0.0108 0 0 0.01 16 0.0286 0 0 0 0 0.0276 0.0645 0.0630 0.1655

Acid volume.

Original total alkaloid.

Factor.

25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

0.1640 0.1640 0.1640 0.1640 0.1680 0.1680 0.1680 0.1680 0.1585 0.1585 0.1585 0.1585 0.1595 0.1595 0.1595 0.1595 0.1595 0.1595 0.1595 0.1595

TABLE XIII. Alkaloid.

Acid.

Strychnine. . . . . . . . . . . .

HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr HTr

,

Brucine. . . . . . . . . . . . . . . Morphine. . . . . . . . . . . . . Cinchonidine. . . . . .....

.

Cinchonine . . . . . .....

Strength.

Chloroform.

.

Vo1um e

Alkaloid.

0

N/2

3:

N&t.

N/2 N/4 N/8 Neut.

x

N)8 Neut. N/4 N N/8 /8 Neut.

20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

0 0 0 0 0 0.0040 0.0032 0 0 0 0 0.0018 0.0018 0 0.0024 0 0 0.0014 0.0023

0

0 0

0 0 0 0.0238 0.0191 0 0 0 0 0.0114 0.0114 0 0.0153 0 0 0.0087 0.0144

829

AMERICAN PHARMACEUTICAL ASS 0CIATION TABLE XII1.-Conlinued. Alkaloid

Acid.

Quinine.. . . . . . . . . .. . . . . Codeine ... . . . , . .. . . .

. ..

..... Aconitine . . . . , . . _.

.

Atropine. . . . .

.....

Veratrine. . . , . . . . . . .. ...

Strength.

Chloroform.

Acid

Volume.

Alkaloid.

volume*

20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

0 0 0.0014 0 0 0 0 0 0 0.0052 0.0060 0 0.0011 0.0014 0.0021 0 0 0 0.0024

25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

HTr N/2 HTr N/4 HTr N/8 HTr N/2 HTr N/4 HTr N/8 HTr Neut. HTr N/2 N)4 HTr N/8 HTr Neut. HTr N/2 HTr ,N/4 HTr N/8 HTr Neut. HTr ~~~. HTr N/2 HTr N/4 HTr N/8 HTr Neut.

Original , tota! Factor. alkaloid.

0.1625 0.1625 0.1625 0.1600 0.1600 0.1600 0.1600 0.1930 0.1930 0.1930 0.1930 0.1585 0.1585 0.1585 0.1585 0.1775 0.1775 0.1775 0.1775

0 0 0.0086 0 0 0 0 0 0 0.0269 0.0310 0 0.0069 0.0088 0.0132 0 0 0 0.0135

TABLE XIV. Alkaloid.

Strength.

Strychnine.. . . ,. . ..

N/2

Brucine .

. . .. .

Cinchonidine. .

N/8 N/4 N/50 Neut. .17N lpercent. Neut. .. N/2

..

Quinine. . . . . . . . . ,

Atropine. . . . . . . . , Morphine. . . . . . . . Aconitine. . . . . . . . . Veratrine.. Codeine

.

... ......

Cocaine.

,

.

N/4 N/8 Neut. .17N N/2

N/4 N/8 Neut. N /2 N)4 N/8 Neut. .034N .034N Neut. .034N .255N .085N .017N .017N N/40 Neut. .034N N/49 Neut. .255N .017N Neut.

Chloroform

Alkaloid.

20 20 20 20 20 50 501 SO? 20 20 20 20

0 0 0 0 0.0127 Traces Traces Traces 0 0 0 0.0143 0.0020 0 0 0 0.0086 0

volume.

50 20

20 20 20 20 20 20 20 50 50 50 50 50 50 50 50 SO? SO? 50 501 SO? 50 50 501

0 0 0 0

0 0.0010 0 Traces 0.0064 0.0130 Traces Traces 0.0374 0 Traces 0.0276 0 Traces 0.0143

Extrac-

v$$:e.

25 25 25 25 25 70 50 50 25 25 25 25 70 25 25 25 25 25 25 25 25 70 70 70 70 70 70 70 70 50 50 70 50 50 70 70

'

0.1745 0.1745 0.1745 0.1745 0.1745 0.2000 0.2610 0.2610 0.1780 0.1780 0.1780 0.1780 0.2000 0.1715 0.1715 0.1715 0.1715 0.1740 0.1740 0.1740 0.1740 0.2000 0.2000 0.2000 0.2000 0.2000 0.2000 0.2000 0.2000 0.2150 0.2150 0.2000 0.2470 0.2470 0.2000 0.2000 0.2640

0 0 0 0 0.0727 0 0 0 0 0 0 0.0803 0.0100 ._ 0 0 0 0.0503 0 0 0 0

0 0

0.0050 0 0 0.0320 0.0650 0 0 0.1780 0 0 0.1116 0 0 0.0540

References.

Authors Authors Authors Authors Authors Kippenberger Simmer Simmer Authors Authors Authors Authors Kiuuenbereer Adthors Authors Authors Authors Authors Authors Authors -4uthors Kippenberger Kippenberger Kippenberger Kippenberger Kippenberger Kippenberger Kippenberger Kippen berger Simmer Simmer Kippenberger Simmer Simmer Kippenberger Kippenberger Simmer

JOURNAL OF THE

830 Acid-Hydrochloric

TABLE XV.

Acid:

Alkaloid.

Strength.

Strychnine. . . . , . . .

N/2

Chloroform volume.

20 20 20 20 50 502 SO? SO? SO? 502 50 20 20 20 20 SO? 501 502 SO? 150 50 507 502

x

Neut. 6.75N 6.85N 2.74N .274N .027N Neut. Bmcine. . . . . . . . _ . .075N Cocaine. . . . .

Neut. 2.74N .274N

.027N

SO? ...

50 502 502 502 50 SO SO? SO? 501 50 SO?

Neut.

Neut. Codeine. . . . . . . . . . .030N 2.74N .027N Neut. Acid-Sulphuric

SO? SO?

Alkaloid.

0.0522 0.0424 0.0394 0.0085 0.0920 0.0233 ..-~. 0.0559 0.0250 0.0083 0.0158 0.0898 0 0 0.0432 0.0432 0.0075 0.0045 0.0037 0.0490 0.0021 0.0014 0.0028 0 0 0 0 0 0.0045 0.0971 0.0807 0.1248 0.0327 0.0530 Traces 0.0079 0.0015 0.03 7 1

Acid, strength*

Strychnine. . . . . . . . . . . . . . . . . . . . . . Bmcine. . . . . . . . . . . . . . . . . . . . . . . . . Morphine .......................

N/2 N/4 N /8 Neut. N/2 N'4 N/8 Neut.

Cinchonidine. . . . . . . . . . . . . . . . . . .

N N/2 /2 Nj8 Neut. N/2

Quinine.. . . .

N/4 Neut. N/8 N /2

.

. ..

..... .

.

I

.

.

.

25 25 25 25 70

so .~

50 50 50 50 70 25 25 25 25 50 50 SO 50 70 70 50

50 .~

50 70 50 50 50 70 70 50 50 50 70

so -. 50 50

alkaloid.

E%?factor.

References.

0.080 0.080 0.080 0.080 0.200 0.2377 0.2377 0.2377 0.2377 0.2377 0.2000 0.1790 0.1790 0.1790 0.1790 0.2240 0.2240 0.2240 0.2240 0.2000 0.2000 0.2250 0.2250 0.2250 0.2000 0.2470 0.2470 0.2470 0.2000 0.2000 0.2110 0.2110 0.2110 0.2000 0.2340 0.2340 0.2340

0.2895 0.2360 0.2182 0.0472 0.4600 0.1020 0.2360 0.1050 0.0340 0.0665 0.4490 0 0 0.2420 0.2420 0.0335 0.0210 0.0165 0.4900 0.0110 0.0070 0.0124 0 0 0 0 0 0.0182 0.4850 0.4035 0.5920 0.1550 0.2520 0 0.0338 0.0064 0.0158

Authors Authors Authors Authors Kippenberger Simmer Simmer Simmer Simmer Simmer Kippenberger Authors Authors Authors Authors Simmer Simmer Simmer Simmer Kippenberger Kippenberger Simmer Simmer Simmer Kippenberger Simmer Simmer Simmer Kippenberger Kippenberger Simmer Simmer Simmer Kippenberger Simmer Simmer Simmer

TABLE XVI.

Acid: Alkaloid.

Codeine. .

v$2e.

.....

.. Neut.

Ether. Volume. Alkaloid.

20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

0 0 0 0.0027 0 0 0 0 0 0 0.0011 0.0019 0 0 0 0.0040 0 0

0 0 0 0 0.0024 0

Acid vo'ume'

alkaloid.

o

~

Extraction ~ ~ factor'

25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

0.1745 0.1745 0.1745 0.1745 0.4780 0.1780 0.1780 0.1780 0.1730 0.1730 0.1730 0.1730 0.1715 0.1715 0.1715 0.1715 0.1740 0.1740 0.1740 0.1740 0.1720 0.1720 0.1720 0.1720

0 0 0 0.0055 0 0 0 0 0 0 0.0063 0.0010 0 0 0 0.0237 0 0 0 0 0 0 0.0139 0

'

831

AMERICAN PHARMACEUTICAL ASSOCIATION TABLE

XVII.

Chloroform. Alkaloid.

Aconitine . . . . . . . . . . . . . .

Acid.

HTr HTr HTr HC1 HC1 HCl HTr Atropine. . . . . . . . . . . . HTr HTr Brucine. ............. HTr HTr HTr Sulph. Sulph. Sulph. HC1 HC1 HC1 HTr Cinchonidine. . . . . . . . HTr HTr Sulph. Sulph. Sulph. HCl HC1 HC1 Cinchonine. . . . . . . . . . . . . HTr HTr HTr Sulph. Sulph. Sulph. HC1 HCl HCI . . . HTr Cocaine. ........ HTr HTr Sulph. Sulph. Sulph. HCl H C1 HCI HTr Codeine. ............ HTr HTr Sulph. Sulph. Sulph. HCI HCl HC1 Quinine. . . . . . . . . . . . .... HTr HTr HTr Sulph. Sulph. Sulph. HC1 HCl HCI

Volume.

20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

a

Original alkaloid.

Acid volume.

0.200 0.200 0.200 0.200 0.200 0.200 0.150 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200

25 50 50 25 25 25 25 25 25 25 25 25 25 25 25 '25 25 25 25 50 50 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

Weight Extraction. in acid factor. alkaloid.

0.200 0.200 0.200 0.165 0.174 0.186 0.149 0.199 0.200 0.200 0.192 0.200 0.200 0.199 0.198 0.1232 0.1417 0.1555 0.200 0.200 0.200 0.200 0.200 0.1988 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.1998 0.200 0.200 0.200 0.200 0.200 0.198 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200

1.oo 1.oo 1.00 0.830 0.872 0.930 0.994 0.996 1.00 1.00 0.964 1.00 1.00 0.996 0.994 0.617 0.7088 0.777 1.oo 1.oo 1.oo 1.oo 1.00 0.996 1.00 1.oo 1.oo 1.oo 1.00 1.oo 1.oo 1.oo 0.998 1.oo 1.00 1.oo 1.oo 1.00 0.990 1.OO 1.oo 1.oo 1.oo 1.00 1.00 1.oo 1.oo 1.oo 1.oo 1.oo 1.oo 1.00 1.oo 1.oo 1.oo 1.00 1.00 1.oo 1.oo 1.00 1.oo 1.oo 1.00

JOURNAL O F THE

832

TABLE XVII-Continued Alkaloid.

Strychnine. . . . . . . . .

Acid.

HTr HTr HTr HTr HTr HTr HTr HTr HC1 HC1

Chloroform. Strength.

4N 2N

N

N/2

N /4

"$2 N/25

N //42 N/8 N/2 N/4 N/8 N/2

3 : Nj2

3:

Volume

20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

Original alkaloid.

0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200 0.200

p2p:

Acid

volume. 50 100 100 100 95 75 75 25 25 25 25 25 25 25 25 . 25 25 25 25 25

alkaloid.

0.200 0.200 0.198 0.198 0.198 0.198 0.197

037 \

0.179 0.175 0.179 0.198 0.196 0:200

0.200 0.200 0.200 0.126 0.148 0.157

Extraction factor

1.00 ~

~~

1.00 0.996 0.996 0.996 0.996 0.986 0.938 0.900 0.875 0.899 0.990 0.990 1.00 1.00 1.00 1.00 0.630 0.742 0.787

V. DISCUSSION O F RESULTS.

In looking over the tables, the following results will be observed : Aconitine.-ln the washing of a solution of aconitine tartrate with chloroform, it is seen that the more concentrated the acid is, the less alkaloid will be removed. Hydrolysis takes place in the neutral solution with the removal of about 11 percent of the alkaloid in the free state. Whatever alkaloid is removed from the acid solution is removed in the form of salt and not in the free state. Aconitine is also removed from solution in sulphuric acid, provided the acid is less than*concentration, but in much smaller amounts than from tartaric acid. From hydrochloric acid solution the amount of alkaloid removed is in direct proportion to the strength of the acid and the alkaloid is almost entirely removed as the salt, showing that chloroform is a fairly good solvent for the hydrochlorides of aconitine. Atropine.-The same phenomena will be observed in the cases of the sulphates and tartrates of atropine, namely, that as acidity increases, less alkaloid will be removed by ether or chloroform. With the hydrochlorides it is reversed, and a s the strength of the acid increases, the amount of alkaloid removed increases, and i t is removed as the salt. Brucine.-Brucine is not removed from tartaric acid solutions of strength .greater than $ by either chloroform or ether, although with a decrease in the concentration of the acid from that point down, there is increased hydrolytic action with the removal of the alkaloid in the uncombined state. Sulphuric acid retains the alkaloid from removal by either chloroform or ether from acid solution, and N ether does not even extract any from the neutral solution. From a o.0 75 solution of the hydrochloride in hydrochloric acid, 45 percent of the alkaloid is removed by chloroform and most of it. as the salt. Cinchonidine and Citdzonine.-Cinchonidine, cinchonine, and quinine differ from the other alkaloids in that their hydrochlorides are insoluble in chloroform. Many of the hydrochlorides of the other alkaloids are soluble to a great extent in this solvent. The neutral tartrates and sulphates are hydrolyzed and the alkaloids removed by both ether and chloroform. Cinchonidine differs from cinchonine

AME'RICAN PHARMACEUTICAL ASSOCIATION

833

in that the tartrates are hydrolyzed in acid solution and some of the alkaloid removed as free cinchonidine. Quinine.-Quinine sulphate is neither hydrolyzed in neutral and acid solution nor is the salt soluble in either ether or chloroform. The neutral tartrate is only slightly soluble in water but the acid solution is hydrolyzed to a slight extent, giving up quinine in both the free and combined condition to chloroform and in the free state to ether. Morphine.--Neither chloroform nor ether remove morphine from the neutral or acid solution of the tartrate. The neutral sulphate is slightly hydrolyzed and some free morphine found in the ether. Strychnine.-Hydrolytic action takes place in the+ tartaric acid and neutral solution of the strychnine tartrate and some alkaloid is removed by the chlorofonn in the free state. Increase in acidity with both the sulphates and tartrates causes a decrease in the amount of alkaloid removed, the reverse being true in the case of the hydrochlorides. Yeratrim.-Veratrine is removed in appreciable amounts from the tartaric acid solution by chloroform, but only from the neutral solution by ether. Chloroform does not take up any of the alkaloid from the sulphuric acid, but appreciably lowers the concentration of the alkaloid in the hydrochloric acid solutions. Codeine.-Neither ether nor chloroform will remove codeine from solution in +Or+ tartaric acid, but chloroform removes increasing amounts as the concentration of the acid decreases from that point on. The hydrochlorides are more soluble in chloroform the greater the concentration of the acid. Hydrolysis takes place in the neutral solutions and much codeine is removed. In general, the following principles may be apparent in the foregoing: 1. The neutral sulphates and tartrates in aqueous solution are hydrolyzed to a certain extent with the subsequent formation of free alkaloid and acid. This alkaloid may be removed by the immiscible solvent. 2. With an increase in the acidity of the solution the hydrolytic action becomes less and the amount of alkaloid taken up in the free state decreases with the increase in acidity. 3. Many of the acid sulphates and tartrates are removed as salts to a slight degree by chloroform and ether. 4. The alkaloidal hydrochlorides tend to be quite soluble in chloroform, and in such cases the solubility increases with the acidity of the solution, in all the cases studied. By means of this data, the following questions may be answered: 1. What conditions of acidity would completely remove the alkaloid from its chloroform solution? 2. Which solvent, chloroform or ether, can best be used for shaking out the neutral or acid solution of the alkaloidal tartrates o r sulphates, without removing the alkaloid ? 3. And which salts are least easily removed by chloroform or ether, and in what concentration of acid, either by hydrolysis o r through the solubility of the salt itself in the immiscible solvent? 1. The best conditions of acidity for completely removing the alkaloids from the chloroform solution. Table XVIII gives the values for the extraction of 0.2 Gm. of the alkaloid from 20 Cc. of the solvent chloroform, by the different acids :

JOURNAL OF THE

834

TABLE XVIII. Alkaloid.

Acid.

Strength.

Aconitine.. . . . . . . . . . . . . . . . . . .

HTr

N/8 N/8 N/8 N/8

2 portions of 25 Cc. each 1 portion of 25 and 1 of 10 Cc. 1 portion of 25 and 1 of 10 Cc. 25 c c .

Cinchonine . . . . . . . . . . . . . . . . . . . Cocaine. ..................... and Codeine...................... Quinine ......................

Sulph. Sulph.

N/8 N/8

1 portion of 25 and 1 of 10 Cc. 25 c c .

HC1 HCl HTr Sulph. HTr HTr Sulph.

N/8

25 c c . 25 c c . 25 c c . 25 c c . 3 portions of 25 Cc. each 25 c c . 25 cc.

Strychnine. Veratrine . .

.

Volume.

%!

*

N/8 N/8 N/8 N/8

2. The best solvent for shaking out the neutral and acid solutions of the alkaloidal tartrates, without the loss of alkaloid: TABLE XIX. Alkaloid.

Strength HTr.

Solvent.

Aconitine.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ether

. . . . . . Chloroform . . . . . . Chloroform . . . . . . Ether

..............................

..................... ............................. Strychnine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Veratrine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chloroform Ether Either one Ether Ether

N /4 Slightly acid N/8 Slightly acid N/8 Ti/8 N/8 Slightly acid Slightly acid Slightly N/8

Percent alkaloid removed.

0 1 .o 1.5 1.2

0 0 0.8 0 0 0

3. The salts that are least easily removed by chloro'forin or ether and the best concentration of acid : TABLE XX. Chloroform. Alkaloid.

Salts.

Aconitine . . . . . . . . . . . . . . . . . . . . Sulphate Tartrate Atropine. . . . . . . . . . . . . . . . . .. . . HC1 Brucine. . . . . . . . . . . . . . . . . .... . Sulphate Cinchonine. . . . . . . . . . . . . . . . . . . Tartrate Cinchonidine. . . . . . . . . . . . . . . . . Sulphate Codejne . . . . . . . . . . . . . . . . . . .. . . Sulphate Quinine. . . . . . . . . . . . . . . . . . . . . . Sulphate Morphine . . . . . . . . . . . . . . . . . . . . Sulphate Strychnine. . . . . . . . . . . . . . . .. . . Sulphate Veratrine . . . . . . . . . . . . . . . . . . . Sulphate

Ether.

Stren t h acii.

Percent removed.

N/4 N/4 0.02N N/8 N/8 N/8 N/50 N/50 N/50 N/50 N/50

0 0 0 0 0 0 0

0 0

0 0

Salts.

Stren t h acig.

Percent removed.

Tartrate

s/4

0

Sulphate Sulphate Tartrate Tartrate Sulphate Sulphate Tartrate Tartrate Tartrate

N/10

0 0 0.8

Nj8

0 0 0 0 0 0

In addition, calculations may be made which will tell how many shakings from chloroform solution need be made by an acid to completely remove the alkaloid from the chloroform solution. If 94 percent of the alkaloid is removed in the first shaking with 25 Cc. of acid, the second extraction will remove 94 percent of the 6 percent left, or 5.86 percent. Thus these two extractions will remove 99.86 percent of the alkaloid. A third extraction will take away 94 percent of the remaining 0.14 percent, or 0.131 percent, so the three extractions with the acid will make practically a complete removal.

AMEXICAN PHARMACEUTICAL ASSOCIATION

835

Table XXI shows the number of shakings necessary to remove 0.2 Gm. of alkaloid from 20 Cc. of a chloroform solution. TABLE XXI.

\

Acid.

Alkaloid.

Aconitine.. . . . .

. . ..

Atropine. . .

. .. ...

Brucine. . . .

.. . ...

Cinchonidine

.... ..

Cinchonine

..,...

Cocaine. . . . . ,

, , . , ,

..

..

Codeine

..

Quinine

. . .. .

HTr HTr HTr HCl HCl HCl HTr HTr HTr HTr HTr Sulph Sulph. Sulph. HC1 HC1 HC1 HTr HTr HTr HCl HCl HC1 Sulph. Sulph. Sulph. HTr HTr HTr HCl HCl HCI Sulph. Sulph. Sulph. HTr HTr HTr Sulph. Sulph. Sulph. HC1 HC1 HC1 HTr HTr HTr Sulph. Sulph. Sulph. HC1 HC1 HC1 HTr HTr ~ _ HTr Sulph. Sulph. Sulph. HCl HC1 HC1

Percent alkaloid removed in first shaking.

Number of shakings for complete removal.

100 100 100 83.0 87.2 93.0 99.4 99.6 100 100 96.4 100 99.6 99.4 61.7 70.8

1 1

1 4

3 3 2 2 1 1

77.7

_ .

100 100 100 100 100 100 100 100 99.5 100 100 100 100 100 100 100 100 99.8 100 100 99.0 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

'

2 1 2 2 6 5 4 1 1 1 1 1 1 1. 1 1 1 1 1 1 1 1 1 1 2 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

,

Total acid v o1ume

.

25 25 25 100 75 75 35 25 25 25 35 25 35 . 35 150 125 100 25 25 25 25 25 25 25 25 35 25 25 25 25 25 25 25 25 ~. 35 25 25 35 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 ~~

JOURNAL O F THE

836

TABLE XXL-Continued. Alkaloid.

Acid.

Strength'

Strychnine. . . . . . . . . .

HTr HTr HTr HTr HTr HTr HTr HTr

N Nd2

Veratrine..

. . . . . . . .. .

Percent alkaloid, removed rn first shaking.

Number of shakings for complete removal

Tot a1 acid volume.

100 After 2 shakings of 25 Cc. each After 4 shakings of 25 Cc. each 100 99.6 After 4 shakings of 25 Cc. each 99.6 After 4 shakings of 25 Cc. each N12 99.6 After 4 shakings(3X25+ 1OCc.) N 14 99.6 After 3 shakings of 25 Cc. each 99.6 After 3 shakings of 25 Cc. each 2!$! N/25 93.8 After 1 shaking of 25 Cc. For complete removal from N/25 acid, 2 shakings. 90.0 3 75 HCl N/2 87.5 3 75 HC1 N 14 89.9 3 75 HC1 N/8 99.0 2 35 HTr N12 98.0 2 35 HTr ~ 1 4 100.0 1 25 HTr N 18 63.0 6 150 HC1 N12 74.2 5 125 HC1 N 14 4 100 78.7 HC1 N18 100 1 25 Sulph. N12 100 1 25 Sulph. N 14 100 1 25 Sulph. N/8

VI. S U M M A R Y .

1. The most practical method for the determination of alkaloids involves the extraction of the alkaloid from an aqueous solution by means of an immiscible solvent, such as chloroform or ether. 2. It further involves the purification of the alkaloidal solution by removal of gums, colors, etc., by similar methods. 3. Unless conditions are carefully guarded, loss of alkaloid as salt o r in the free state will occur during the extraction. 4. The equilibrium conditions for the following systems have been established, in the case of the alkaloids aconitine, atropine, brucine, cinchonidine, cinchonine, cocaine, codeine, morphine, quinine, strychnine, and veratrine : ( a ) The. alkaloidal tartrates, tartaric acid, water and chloroform. ( b ) The alkaloidal tartrates, tartaric acid, water and ether. ( c ) Certain alkaloidal sulphates, sulphuric acid, water, and chloroform. ( d ) Certain alkaloidal sulphates, sulphuric acid, water, and ether. ( e ) Certain alkaloidal hydrochlorides, hydrochloric acid, water, and chloroform. (f) The extraction factors have been determined for all these systems, as well as those described in the literature, and the most favorable conditions for extraction calculated. LABORATORY OF ORGANIC ANALYSIS OF

THE

UNIVERSITY OF ILLINOIS.

BIBLIOGRAPHY. Dragendorff : Die gerichtlich-chemische Ermittelung von Giften, 4 Aufl., p. 151. ' Stas-Otto : Ausmittelung der Gifte., 7 Aufl., pp. 144 and 280. 'Kippenberger, C . : Grundlagen fur den Nachweis von Giftstoffen bei gerichtlich-chemischen Untersuchungen, p. 56. ' Kippenberger, C. : Zts. f . Anal. Ch., 1900,39, 290-314. ' Proelss, Hans : Apoth. Ztg., 1900, 16, 289493. ' Springer, Ed. : Apoth. Ztg., 1901, 17,225-226. ' Simmer : Arch. d. Phar., 1906,244,672. 0 Marden and Elliott : J. Ind. Eng. Ch., 6, 928. ' Kippenberger, C . : Zts. f. Anal. Ch., 1900, 39, 201-230.